Castle Yankee
Encyclopedia
Operation Castle
Operation Castle was a United States series of high-energy nuclear tests by Joint Task Force SEVEN at Bikini Atoll beginning in March 1954...
series of American tests
Nuclear testing
Nuclear weapons tests are experiments carried out to determine the effectiveness, yield and explosive capability of nuclear weapons. Throughout the twentieth century, most nations that have developed nuclear weapons have tested them...
of thermonuclear bombs.
Jughead
Yankee was originally intended to be a test of a simplified and lightened bomb version (the TX-16, or "emergency capability" EC-16Mark 16 nuclear bomb
The Mark 16 nuclear bomb was a large thermonuclear bomb, based on the design of the Ivy Mike, the first hydrogen bomb test fired. The Mark 16 is more properly designated TX-16/EC-16 as it only existed in Experimental/Emergency Capability versions....
) of the large and complex cryogenic device (the first successful multi-stage fusion
Nuclear fusion
Nuclear fusion is the process by which two or more atomic nuclei join together, or "fuse", to form a single heavier nucleus. This is usually accompanied by the release or absorption of large quantities of energy...
device) tested in Ivy Mike
Ivy Mike
Ivy Mike was the codename given to the first United States test of a thermonuclear weapon, in which a major part of the explosive yield came from nuclear fusion. It was detonated on November 1, 1952 by the United States at on Enewetak, an atoll in the Pacific Ocean, as part of Operation Ivy...
. A small number of EC-16s were produced on an emergency basis to provide a stop-gap thermonuclear weapon capability in response to the Russian nuclear weapons program.
The test device, code-named "Jughead", had been prepared as a backup in case the non-cryogenic "Shrimp" fusion device (first tested in Castle Bravo
Castle Bravo
Castle Bravo was the code name given to the first U.S. test of a dry fuel thermonuclear hydrogen bomb device, detonated on March 1, 1954 at Bikini Atoll, Marshall Islands, as the first test of Operation Castle. Castle Bravo was the most powerful nuclear device ever detonated by the United States ,...
) failed to work. The test of "Jughead" was cancelled when the Bravo device was successful, and the few EC-16s which were actually built were withdrawn and dismantled.
Runt II
Jughead was replaced in the Yankee test by the so-called "Runt II" device (the TX-24 bomb, initially the "emergency capability" EC-24), a modified form of the "Runt" device (the TX-17/EC-17) tested in Castle RomeoCastle Romeo
Castle Romeo was the code name given to one of the tests in the Operation Castle series of American nuclear tests. It was the first test of the TX-17 thermonuclear weapon , the first deployed U.S...
. Externally identical, the principal difference between them was in the fuel for the fusion stage. While Runt used natural lithium
Lithium
Lithium is a soft, silver-white metal that belongs to the alkali metal group of chemical elements. It is represented by the symbol Li, and it has the atomic number 3. Under standard conditions it is the lightest metal and the least dense solid element. Like all alkali metals, lithium is highly...
(with 7.5% of the Lithium-6 isotope
Isotope
Isotopes are variants of atoms of a particular chemical element, which have differing numbers of neutrons. Atoms of a particular element by definition must contain the same number of protons but may have a distinct number of neutrons which differs from atom to atom, without changing the designation...
), Runt II used the same partially enriched lithium (approximately 40% Lithium-6) as the "Shrimp" device tested in Bravo.
It was detonated on May 5, 1954, at Bikini Atoll
Bikini Atoll
Bikini Atoll is an atoll, listed as a World Heritage Site, in the Micronesian Islands of the Pacific Ocean, part of Republic of the Marshall Islands....
of the Marshall Islands
Marshall Islands
The Republic of the Marshall Islands , , is a Micronesian nation of atolls and islands in the middle of the Pacific Ocean, just west of the International Date Line and just north of the Equator. As of July 2011 the population was 67,182...
, on a barge moored in the middle of the crater from the Castle Union
Castle Union
Castle Union was the code name given to one of the tests in the Operation Castle series of American nuclear tests. It was the first test of the TX-14 thermonuclear weapon , one of the first deployed U.S...
test.
Although it has been predicted to produce a yield of 6 to 10 megatons
TNT equivalent
TNT equivalent is a method of quantifying the energy released in explosions. The ton of TNT is a unit of energy equal to 4.184 gigajoules, which is approximately the amount of energy released in the detonation of one ton of TNT...
, it actually produced a yield of 13.5 megatons, the second-largest ever yield in a U.S. fusion weapon test. Like the Ivy Mike
Ivy Mike
Ivy Mike was the codename given to the first United States test of a thermonuclear weapon, in which a major part of the explosive yield came from nuclear fusion. It was detonated on November 1, 1952 by the United States at on Enewetak, an atoll in the Pacific Ocean, as part of Operation Ivy...
, Bravo and Romeo tests, a large percentage of the yield was produced by fast fission
Nuclear fission
In nuclear physics and nuclear chemistry, nuclear fission is a nuclear reaction in which the nucleus of an atom splits into smaller parts , often producing free neutrons and photons , and releasing a tremendous amount of energy...
of the natural uranium
Uranium
Uranium is a silvery-white metallic chemical element in the actinide series of the periodic table, with atomic number 92. It is assigned the chemical symbol U. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons...
"tamper"; 7 megatons of the yield were from this source. The other 6.5 megatons were from fusion reactions; this increase was due to the different fusion fuel. This fusion yield was the largest to date, and set a record that stood for several years.